Papers by Keyword: Pneumatic Measurement

Abstract: It is presented that a novel concept to estimate the shape of inner hole and calculate the location of reversing point in course of honing in this paper. Based on analysis of machining condition, Simplified slope measurement model is established in pneumatic measurement system for inner hole honing. The method and principle are elaborated in this article. The model can accurate the accuracy of machining area in inner hole. Program module was designed and written for experiment. And the experimental data show that the measuring model is feasible

Abstract: Aiming at the problem of gross error in datasets of form tolerance pneumatic measurement, which have the characteristics of small sample and non-statistical distribution, a new fuzzy assessment based method for detecting and rejecting the gross error is proposed. The detecting principle and its procedure are elaborated, and some correlative problems, including the valuation of fuzzy optimal factor and calculation of fuzzy available interval are also discussed in detail. Using an actual dataset in pneumatic measurement of form tolerance to calculate, the results demonstrate the effectiveness and consistency of the proposed method and it can be used to detect and reject the gross error of the measurement sequence in a rapid, simple and reliable way by comparison with the traditional methods based on statistical theory. And it is well suited for detecting gross error in various measurement processes with the measured datasets of small sample and non-statistical distribution.

Abstract: Pneumatic measurement and genetic algorithm based approach for form tolerances, including the cylindricity error, circularity error and straightness error of axis, of inner hole in spool valve are studied in this paper. A differential pressure type of pneumatic comprehensive measurement approach is put forward, which applies the pneumatic nozzle scanning measurement principle. The minimum zone evaluation and calculation approach for form tolerances based on an improved genetic algorithm is presented considering the characteristics of the measuring point. Finally, the automatic measurement experiment is developed, which can simultaneously measure and evaluate the form tolerances of inner hole in one process.

Abstract: Process Measurement is a measuring method which is accompanied with process of the manufacture of work piece. This paper puts forward a new concept of fluid process measurement, and provides four types of fluid process measurements, which are, pressure pneumatic process measurement, flow pneumatic process measurement, pressure hydraulic process measurement, and flow hydraulic process measurement, and establishes the mathematical and physical modal for them. This paper also provides an example of the application of this measurement method. This measurement has a good prospect, because it can deal with the work pieces with high-precision, complex shape and which are hard to be measured in the machining process.

Abstract: Spool valve orifice flow characteristic of servo valve plays an important role in the spool valve overlap measurement and manufacturing quality analysis of servo valve. The liner segment of flow characteristic curve could be used to calculate the overlap, and the non-linear segment could be used to evaluate the manufacturing quality of servo valve. This paper analyzed the valve orifice characteristic measurement based on the pneumatic flow method in detail, developed an automatic pneumatic measurement apparatus for valve orifice characteristic and spool valve overlap based on the thermal mass flow sensor AWM2300, verified the measurement accuracy and non-repeated error of this apparatus, and adopted the overlap as investigated object to contrast the measurement results by pneumatic flow method with by pneumatic pressure method. The non-repeated error of overlap measurement by pneumatic flow method did not exceed ±0.5(m, and the experimental results indicated that the automatic pneumatic flow measurement can excellently satisfy the actual requirement in the production of servo valve.

Abstract: For reducing the machining difficulty and increasing the conjunction precision, an automatic sorting system is presented. The system combines the backpressure pneumatic measurement with a pneumatic-electric transfer technology. A semiconductor pressure sensor is used for the pneumatic-electric transfer. The air chamber pressure is converted to an electrical signal. The merits of the semiconductor pressure sensor include high conversion precision, high frequency response, and small volume. But it has a relatively big temperature drift if no compensation is provided. The sensor can compensate temperature drift. But the null shift and sensitivity shift still exist. Reducing supply voltage using an electric bridge or reducing supply current using a constant current source can reduce the shift. The null shift and sensitivity shift can be further reduced by auto-compensation using a calibrated gauge. The automatic sorting system can automatically sort injector valves and orifices quickly with a resolution of 0.2µm. The sorting accuracy is 0.5µm and the speed is approximately thirty pieces per minute. The system has the function of auto-control and error auto-compensation and has a high measuring efficiency and high precision.

Abstract: The non-contact pneumatic measurement technique is useful for dimension measurement. The authors have developed a new type of air-pin pneumatic-electronic sensor. The ultra-precision air-pin sensor and the dynamic characteristics of the sensor are investigated. The measurement accuracy of the air-pin pneumatic-electronic sensor is better than 0.1µm for the 10µm measurement range. The response time is less then 10ms.